06 SS issues

i bought my SS feb 06 with 105 miles on it, before i could pay the first carnote someone stole the tires and rims and then the tow truck did extensive damage to the undercarrige while towing. the dealer did a good job of putting it back together but since then i have had to have both tierods replaced and both wheel bearings. i have also had an issue with the computer loosing its memory and would only work with one key(use one set and car would not start and security lite on use other key and car works fine) i have also had many issues with the trans not shifting properly, im not sure if it is the trans having issues or if it is the cylinder deactivation having problems cause i usually have the trans problem when going between 35-48mph not quite fast enough for the car to shift into overdrive. i have also noticed that when the car switches from 4 to 8 cyl the only way i can tell is by the indicator on the dash but i can always feel it shift from 8 to 4, the rpms rise a few hundred rpm's then drop back down and now its in 4cyl mode. btw i have 32000 miles on it now